This career development proposal will provide a promising early-career researcher, Dr. Sean C. Lucan, with the additional knowledge, tools, and skills needed to become an independent investigator. Dr. Lucan's interest is in how local food environments influence adolescent diet and diet-related health. Dr. Lucan will participate in a variety of training activities and apply lessons directly to an innovative patient-oriented researc project. The project will link dietary data from adolescent patients to data on food sources in the areas around which they live and attend school. The proposed training and research will facilitate transition from supervised study to independent investigation, culminating in the submission of R01 applications that address problems like incident obesity and diabetes for young people transitioning to adulthood. Dr. Lucan and a team of committed mentors and advisers designed a research-and-training plan to address limitations in both the existing scientific literature and in Dr. Lucan's own skill set. Regarding the existing scientific literatur, research suggests that areas around adolescents' homes and schools-most notably in low-income and minority communities-tend to offer predominantly fast foods, processed foods, and other less-healthy convenience items, with few healthy alternatives; such environments are generally associated with poorer diets and poorer health. However, many studies suggesting associations have been limited in several important ways. As a result, it is not clear how to intervene to change environments to make healthier eating an easier option (or an option at all) and unhealthy eating more difficult (or not the only option) for adolescents. The proposed project will build on prior work and be innovative in several important ways. It will rely on adolescent research assistants and geographic information science (GISc) to directly assess a full range of food sources within walking distance of adolescents' schools and homes. The research will assess links between food sources and dietary intake for adolescent patients, capitalizing on a unique health-system dataset: an electronic medical record (EMR) that contains both clinical and survey data. The specific aims are: Aim 1. To conduct a comprehensive assessment of local food sources: Adolescents will assess locations and food offerings for a full range of food sources to which they are exposed around their homes and schools. Aim 2. To generate a novel integrated multi-level database. Dr. Lucan will merge food-source data (from Aim 1) with other local data and with data on individual adolescent patients (from the health-system EMR) Aim 3. To assess how local food sources relate to adolescents' dietary intake. Dr. Lucan will use the database (from Aim 2), to assess how food sources around adolescents' homes and schools relate to their reported dietary intake (e.g., fruit, vegetable, and sugary-drink consumption). Analyses in this K23 work will be cross-sectional but the methods, database, and training will directly lay the foundation for longitudinal study (e.g., how changes i local food environments relate to changes in diet-related health outcomes like incident obesity, diabetes, dyslipidemia, and hypertension-all possible through the clinical data available in the EMR). Longitudinal studies will inform intervention trials that Dr. Lucan can submit as R01 applications towards informing policy changes and improving food environments, diet, and health. Regarding Dr. Lucan's own current skill set, he has identified one major areas of focus for coursework and mentored study (GISc) and three supporting areas (encrypted data management, statistical analyses, and behavioral and social science) that he will need to conduct the type of research that will move the field and his career forward. Dr. Lucan will enroll in a formal certificate program in GISc, and take courses in secure-data handling, multilevel modeling, behavioral and social-science theory. These learning activities, along with mentored study under expert mentors, will find practical application in the proposed research: GISc to define 'exposures' to local food sources, data management to link diverse datasets, behavioral and social-science theory to inform multilevel analyses, and regression modeling and GISc to analyze associations. The research and training activities will produce a confident patient-oriented researcher with the skills to conduct studies involving sensitive, multilevel, diverse, spatial data. Training will occur in a superlative research and learning environment. Both the institution and department rank highly in NIH funding and there are exceptional resources, facilities, personnel, partnerships, and expertise to support Dr. Lucan's project and training needs. There is experience with multilevel GISc considerations in patient-oriented research and tremendous expertise in behavioral and social sciences, nutrition studies, and research involving adolescents. Veteran supervising faculty has wide-ranging current and historical ties to NICHD. The proposed work will provide Dr. Lucan the training and the practical experience to support a career as an independent investigator.